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The Progressive Suspension variable rate springs for my '88.

 

Oil level is 5.5" from the top (Prolly measured from the back of the tube) with forks collapsed and nothing in the fork (no spring or spacer installed), IE do this first!

 

The Instructions say to remove the small spring and the washer between it and the big spring. Well, I don't have that set up; my small spring isn't in the same tube as the big spring so the small spring stays?

 

The plastic spacers supplied with the spring kit, do I use them, do I shorten them, if so how much. figure passenger wt. as 400lbs. Do they go on top of the spring?

 

What is the order of assembly after the spring is in? I think the spring goes in, then the washer and then the spacer. What goes in next?

 

How is the inner tube held while torquing the screw with the copper washer/seal?

I temp installed a progressive spring hoping it would provide enough downward force to allow me to torque the screw to the spec'ed 14 ft.lbs but no joy!

Edited by dna9656
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Checking the oil level without the springs in the leg is valid for the OE springs. Since the Progressive springs will occupy more space the oil level will be slightly higher with them. I don't know if the difference is enough to matter. From what I've read on this site different owners have used different length spacers. I think at least one didn't use them at all. Others have cut them to 1/2", 1 " etc if memory serves. I haven't actually replaced mine yet so others will now more than I about this subject. There are a lot of threads on this subject if you have the time to search and read them.

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Checking the oil level without the springs in the leg is valid for the OE springs. Since the Progressive springs will occupy more space the oil level will be slightly higher with them. I don't know if the difference is enough to matter. From what I've read on this site different owners have used different length spacers. I think at least one didn't use them at all. Others have cut them to 1/2", 1 " etc if memory serves. I haven't actually replaced mine yet so others will now more than I about this subject. There are a lot of threads on this subject if you have the time to search and read them.

 

Progressive Suspensions says (follow and defer to the OEM instructions to service your fork. You also have to keep in mind that you are modifying the fork so you sort of have to blend the instructions (PS and OEM) along with the guidance and advice you can get here from others who have done exactly what you're doing with the same exact bike. So, add 5.5" oil (measured from the top of the tube) of fully closed fork, cycle the fork up and down fully several times to ensure the air is all out; this further ensures the oil levels are the same. (making SURE you have re-installed the drain screw and the anti-dive units; THEN install the springs, washer, and spacer, if used. THEN torque the hex drive bolt to 14 LBS.

Progressive Suspensions says while it's very important that the oil levels are the same I can't imagine the difference in the oil level being that much different when measured with the forks at a 90 degree angle VS. the angle they are in when installed on the bike. As stressed in the PS instructions it's really important that they are the same. The springs are longer and heavier (the gauge of spring wire) than the OEM springs so they will displace more oil than the OEM springs. When you see the springs side by side you can better appreciate the difference and the amount of oil displacement.

Edited by dna9656
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I was not sure if the oil level was measured at the top or bottom so I went from the middle. I used a 60cc syringe and put a collar on it set to the depth I want. Then just over fill the fork and use the syringe to suck it down the exact level you have preset on the syringe. Fast neat and accurate.

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I went 5.5" on oil level, but I had my forks removed and measured with forks straight up and down (I had done a total fork rebuild). I pumped upper/lower sections occasionally as I slowly added oil. I then added my Progressive springs, installed 5/8"-cut PVC with factory washers on both sides and placed my threaded cap on. I then installed the forks on my bike, connecting everything including the anti-dives.

 

I'm 225 and my wife is 120lbs. I've been riding and I'm thrilled how much better the ride is.

 

Just sharing my experience with new Progressives.

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  • 5 months later...

Gen 1 XVZs run part #11-1112 Progressive fork springs

 

Gen 2 XVZs run part #11-1144 Progressive fork springs

 

 

I've been told by an older Yamaha Tech and Venture guru to add more oil than spec dictates when converting to progressives and to forget about the air. He gave me a specific measurement in milliliters to add but I don't remember the exact number.

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  • 1 month later...

For all those who are servicing their forks I decided to replace my fork oil after some 10+ years. I had a shop put progressive springs in which allowed me to get rid of the front air assist which was leaking. The springs along with a new head tube bearing made a huge difference. So I have the front wheel off and the forks exposed. Opened the drain plug and pulled the cap and spring out. Worked the tubes up and down so I think I have most of the oil out that is going to come out.

 

What is interesting is that the manual says there is something like 14 oz of oil in each fork. There is no way there is anywhere close to 28 oz of oil in the pan I collected oil in. Can you loose fork oil over the years just from riding. I realize complete disassembly might get more oil out but I have them free enough that I can take them out and dump them over to see if any more will come out. I am just wondering how the bike could have been riding as well as it was with what looks like about half the oil in the forks that it was supposed to have.

Edited by Geobob
accidentally posted before completing.
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  • 1 year later...

So the 90 royal crashes into sharp road imperfections like a locomotive into a brick wall. In random order

Get rid of the anti dive? Been trying be sure NO brakes before railroad tracks, LOL

Get rid of the air assist add stiffer springs.

Maint 101, change oil, seals etc.? LOL

Air is bleeding down fairly quickly but bike just woke from a 10 year slumber and it seems like the rate of air leaking out has declined in last few days, 300 miles.

No evidence of fork oil leak, so far I have not been brave enough to pry back the gators, :whistling:

Put on a new front tire rear on order. Metzlers were like new with 99 date codes. :Sad_0241:

No idea if fork oil is original at 40K on the clock. Past it's best used by date? :doh:

Factoid of the day, original fork oil stinks so bad because Japan inc used whale oil as part of the mix, really!

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